Light-sensitive photographic material having exceptionally high resolving power

ABSTRACT

A PHOTOGRAPHIC EMULSION ORTHOMATICALLY SPECTRALSENSITIZED BY ADDING OF A DIMETHINE MEROCYANINE DYE TO AN ULTRAMICROFINE SILVER IODOBROMIDE EMULSION OF LESS THAN 0.1 MICRON IN PARTICLE DIAMETER IS INCREASED IN GAMMA WITHOUT BEING LOWERED IN SPEED THUS RESULTING IN AN IMAGE FREE FROM BLUR DUE TO RADIATION AND EXTREMELY HIGH IN ACUTANCE.

United States Patent Oflice 3,736,145 Patented May 29, 1973 3,736,145 LIGHT-SENSITIVE PHOTOGRAPHIC MATERIAL HAVING EXCEPTIONALLY HIGH RESOLVING POWER Akira Hirata, 27-12, S-chome, Kugayama, Suginami-ku;

and Akio Kobayashi, 5-2, 6-chome, T amadaira, Hinoshi, both of Tokyo, Japan; Eiichi Sakamoto, 12, 5- chome, Hon-machi, Hanno-shi, Hanno, Japan; and Shizuo Saito, 1400 Ohwada-cho, Hachioji-slii, Tokyo, Japan N0 Drawing. Filed Nov. 13, 1970, Ser. No. 69,174 Claims priority, application Japan, Nov. 25, 1969, 44/94,229 Int. Cl. G03c 1/22 US. Cl. 96-140 7 Claims ABSTRACT OF THE DISCLOSURE A photographic emulsion orthomatically spectralsensitized by addition of a dimethine merocyanine dye to an ultramicrofine silver iodobromide emulsion of less than 0.1 micron in particle diameter is increased in gamma without being lowered in speed thus resulting in an image free from blur due to radiation and extremely high in acutance. i

This invention relates to a light-sensitive-photographic material having exceptionally high resolving power which is prepared by adding a specific sensitizing dye in an ultramicrofine emulsion so as to effect spectral sensitization at intended Wavelength region. The present photographic material can be increased in gamma and prevented from irradiation without being injured in photographic speed.

For the art of precise metal working by minute photoetching and for the art of preparing I C, which have recently been developed, there are required photographic dry plates which are extremely high in resolving power. These dry plates are required to have such characteristics that they should have been subjected to orthomatic spectral sensitization with a maximum photographic speed in the vicinity of 540 mu, should be extremely high in resolving power, and should be high in acutance (degree of sharpness) in line image portions. Emulsions capable of providing the above-mentioned characteristics are required to satisfy such conditions that silver halides contained therein should be in the form of ultramicrofine particles (at most 0.1; in diameter), should be free from light irradiation or halation, and should be high in gamma of characteristic curves.

In the case of an emulsion prepared by adding oxacarbocyanine or imidacarbocyanine, which is a typical orthodye for ordinary photographic emulsion, to an ultramicrofine emulsion of less than 0.1 in particle diameter, the spectral sensitization thereof is sufficient, but the gamma valve of characteristic curve thereof is low on the whole and the foot portion thereof has been extended. Accordingly, when a line image is photographed by use of a photographic material containing said emulsion, the acutance of the line image portion is deteriorated. In order to overcome the above-mentioned drawbacks, there are adopted such procedures that the foot portion is cut by incorporation of a proper desensitizer or the gamma is improved by incorporation of an anti-irradiation dye. However, all such procedures lower the photographic speed and hence are not satisfactory. Further, there is adopted such procedure that the particle diameter is made smaller to minimize the irradiation as far as possible. This procedure, however, has such drawbacks that the photographic speed is necessarily lowered and no desired speed can be maintained.

As the result of extensive studies, the present inventors have found that an emulsion, which has been orthomatically spectral-sensitized by adding a dimethine merocyanine dye of the general formula shown later to an ultramicrofine silver iodobromide emulsion of less than 0.1/L in particle diameter, is increased in gamma without being lowered in speed, and can give an image which is free from blur due to irradiation and which is extremely high in acutance.

Such elfects of sensitizing dye are displayed only when the dimethine merocyanine dye employed in the present invention is used in combination with an ultra-microfine 10 silver iodobromide emulsion of less than 0.1, in particle diameter, and cannot be displayed if any one of said components has been substituted by other material. For example, if other sensitizing dye is used in place of the dimethine merocyanine dye employed in the present in- 1 vention, or if particles of more than 0.1g in particle diameter are used in place of the particles of less than 0.1/L

in diameter, no high gamma nor high acutance can be attained. Such effects are characteristics of the dimethine merocyanine dye according to the present invention.

The dimethine merocyanine dye employed in the present invention is represented by the general formula,

alkyl, cyanoalkyl, acetyloxyalkyl, carbamoylalkyl, all l (CH CH=OH aryl or substituted aryl group,

X and X are individually a hydrogen or halogen atom,

or an alkyl, alkoxy or aryl group.

Typical examples of the compound of the above-mew tioned general formula are enumerated below, but compounds usable in-the present invention are not limited only to these.

(2) orrmorr O=C'N 045 The sensitizing dye used in the present invention may 'be added to a photographic emulsion after dissolving the dye in a water-miscible organic solvent such as methanol, ethanol or the like. The sensitizing dye may be added to the emulsion at any stage during the preparation of the emulsion. Generally, however, the sensitizing dye is preferably added immediately before completion of chemical ripening (second ripening), and the amount thereof is desirably 30 to 3,000 mg. per mol of silver halide in the emulsion. The emulsion may have been subjected to known chemical sensitization such as sulfur sensitization or the like, and may have been incorporated with known stabilizer, surface active agent and hardener. Further the dimethine merocyanine dye according to the present invention may be incorporated with other cyanine or merocyanine dye. Ordinarily, the emulsion is coated on such a support as a smooth glass plate, but may be coated on a transparent of opaque film such as triacetate or polyester film.

The present invention is illustrated in further detail below with reference to an example.

EXAMPLE To a photographic emulsion containing silver iodobromide particles of 0.05 in average diameter which had been subjected to chemical ripening, each of 0.1% methanol solutions of the compounds exemplified previously was added in such amount as set forth in the table shown later. After stirring at '50" C. for 5 minutes, the emulsion was incorporated with a suitable amount of the stabilizer 4-hydroxy-6-methyl-l,3,3a,7-tetraza indene, and then coated on a smooth dry plate glass to a dry film thickness of 6, to prepare a green-sensitive photographic material having exceptionally high resolving power.

For comparison, control photographic materials were prepared in the same manner as above, except that carbocyanine dyes of the structures shown below were used as sensitizing dyes.

Control compounds:

6 3. A light-sensitive photographic material according to claim 1, wherein said dimethine merocyanine dye has the structural formula The D-19 developer has the following formulation:

Metal 2.6

Sodium sulfite (anhydrous) 90.0

Hydroquinone 8.0

Sodium carbonate (monohydrate) 52.5 0

Potassium bromide 5.0 (CHDZOH Water to make up 1 1.

Further, a resolving power test chart and a knife edge I image were printed With the same green light on the 0=0- photographic material to measure the resolving power (OHmGOOH ([JHQCIECHS and acutance (degree of sharpness) thereof. The results obtained were as set forth in the table below.

In the table, the green light speed is a value calculated 'by assuming as 100 the value of the control dye (II). 4. A light-sensitive photographic material according to Amount Resolving added (mg. Green power per mol of li ht (number of AgX) speed Gamma Aeutance lines per mm.)

Compound:

1 450 87 9. 0 Excellent 480 750 100 9. 5 Quite excellent. 540 300 89 8. 5 Excellent 480 600 100 8. 5 Quite excellen 540 450 92 9. 1 Excellent 480 450 84 8.5 do 480 600 92 8.0 Quite excellent-..- 540 600 92 8. 5 Excellent--. 430 10 600 84 8.0 430 Control (I) 150 108 5. 6 300 Control (II) 300 100 6.0 300 claim 1, wherein said dimethine merocyanine dye has the structural formula The results set forth in the above table show that the dimethine merocyanine dyes used in the present invention can provide high gamma and extremely high acutance and resolving power as compared with the control carbocyanine dyes.

What we claim is:

1. A light-sensitive photographic material having exceptionally high resolving power, characterized by having a layer of an ultramicrofine silver iodobromide emulsion of less than 0.1g in particle diameter which has been incorporated with a dimethine merocyanine dye of the general formula,

o 1'12 X1 :CH 3H=C N 5. A light-sensitive photographic material according to z claim 1, wherein said dimethine merocyanine dye has the X2 0:C N structural formula wherein O onaton R is a lower alkyl, hydroxyalkyl, carboxyalkyl or sulfo- =OHCH=C N alkyl group or an alkoxyalkyl group in which the l alkoxy portion is substituted by a sulpho group or by a sulpho and a hydroxyl group, 5 (CHmC R and R are individually an alkyl, hydroxyalkyl, carboxyalkyl, cyanoalkyl, acetyloxyalkyl, carbamoylalkyl, allyl (CH CH=CH aryl or substituted aryl group, and X and X are individually a hydrogen or halogen atom, or an alkyl, alkoxy or aryl group. 2. A light-sensitive photographic material according to claim 1, wherein said dimethine merocyanine dye has the structural formula 6. A light-sensitive photographic material according to claim 1, wherein said dimethine merocyanine dye has the structural formula 7 7. A light-sensitive photographic material according to References Cited claim 1, wherein said dimethine mercocyanine dye has the i UNITED STATES ATENTS structural formula 2,839,403 6/1958 Knott; 96--127 (CHmOH 2,839,404 6/1958 Knott 96127 0 5 5 2,828,203' 3/1958 MacWilliam 96-140 2,691,652 10/1954 Van Lare 96-137X 1. TRAVIS BROWN, P rir nary Exaininer JHQOCHr 10 J. L. GOODROW, Assistant Examiner US. Cl. X.R. 96132 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,736,145 k Dated M y 29, 1973 Inventofl's) Akira Hirata, Akio Kobayashi, Eiichi Sakamoto,

- a Shizuo Saito It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

r- In the heading at Column 1, insert after the names of q the inventors I A signors to Konishiroku Photo Industry Co. Ltd.

Signed and sealed this 4th day of February 1975.

(SEAL) Attest:

McCOY M. GIBSbN JR c MARSHALL I E v DANN Attestmg Offlcer I Commissioner of Patents 

